Carbon dioxide discharge device



Dec. 27, 1960 H. v. WILLIAMSON CARBON DIOXIDE DISCHARGE DEVICE Filed Sept. 2, 1958 United States Patent() CARBON DIOXIDE DISCHARGE DEVICE Hilding V. Williamson, Chicago, lll., assignor, by mesne assignments, to Chemetron Corporation, Chicago, lll., a corporation of Delaware Filed Sept. 2, 1958, Ser. No. 758,278

9 Claims. (Cl. 62-52) This invention relates to devices for discharging liquid carbon dioxide from a storage vessel to a point of use, and deals more particularly with novel apparatus of this character especially adapted for use in situations wherein the discharge is repeatedly started and stopped.

In the use of liquid carbon dioxide, for cooling or other purposes, it is oftentimes desirable to intermittently discharge quantities of the material to a point of use, instead of employing a continuous, uninterrupted flow. The conditions existing at the point of use, and which are affected by the carbon dioxide, may, for example, in some instances be more effectively controlled by the intermittent type of discharge. One disadvantage attendant this type of operation, however, has been the tendency of the discharge device, under certain conditions, to become clogged with solid carbon dioxide for various reasons which are a result of the intermittent ow.

For example, in one type of cooling system a bath of liquid, such as alcohol, is cooled by the introduction of low temperature carbon dioxide. This is accomplished by means of an injection pipe which is provided with a discharge orifice located below the surface of the bath. Liquid carbon dioxide is supplied to the pipe and a shutot valve is provided in the supply line at a point external of the bath and adjacent the inlet end of the injection pipe. As the liquid carbon dioxide ows through the orifice it is reduced in pressure to that exsiting in the bath, which is generally close to atmospheric and well below the triple point pressure of approximately 75 p.s.i.g. Consequently, the discharged carbon dioxide is released in the bath as a mixture of vapor and snow which has a temperature of as low as 110 F.

Since the injection pipe is at least partially submerged in the bath of liquid being cooled, the pipe may become as cold as the bath itself. So long as the ow of liquid carbon dioxide is maintained, no diiiiculty is generally encountered in the pipe, but when the shut-off valve is closed, part of the residual liquid carbon dioxide in the system between the valve and the discharge orice tends to solidify and clog the pipe as the pressure falls below the triple point. If the injection pipe vextends downwardly from the top of the bath with the orifice located in the bottom of the pipe, the vapor formed as the pressure starts to fall below the triple point will expand in the pipe above the remaining liquid and may force an appreciable amount of the liquid from the pipe before it changes phase.

Also, when the ow of carbon dioxide to the injection pipe is shut ol, the pipe is cooled by the bath to the temperature of the latter. As noted above, this temperature may be as low as 110 F., and usually is at least well below the triple point temperature of approximately 69.9 F. When the ow is again initiated the liquid carbon dioxide which contacts the cold pipe may solidify on the inner surface of the pipe and, either by clogging the pipe or the orifice, interrupt the ow through the pipe. In fact, if the pipe is long enough, or the ow of liquid carbon dioxide slow enough, solid carbon dioxide may "ice,

form on the walls of the pipe even under continuous discharge conditions.

It is the primary object of this invention to provide a carbon dioxide discharge device which is especially designed to minimize the possibility of the carbon dioxide solidifying in the device as a result of intermittent operation of the system.

Another object of the invention is to provide a device of the above mentioned type in which the liquid carbon dioxide remaining in the device, after the flow thereto is stopped, is automatically expelled therefrom.

Another object of this invention is to privide a device of the above mentioned type in which the tendency towards clogging upon initiating the flow is eliminated or greatly reduced.

Other objects and advantages of the invention will become apparent by reference to the following specification taken in conjuction with the accompanying drawings.

In the drawings:

Figure l is a vertical sectional view of a system embodying the invention; and

Figure 2 is a longitudinal sectional view of the injection pipe of Fig. 1.

In the drawings, wherein is shown a preferred embodiment of this invention, there is illustrated a container 10 within which is conned a bath of liquid 12 to be cooled. The actual structure of the container 10 may vary widely, depending upon the particular application, and hence its structure will not be described in detail other than to state that its walls and bottom are provided with suitable heat insulating material 14 to minimize the transfer of heat through the container 10 to the bath 12.

A cover plate 16 is supported upon the side walls of the container and is provided with an opening 18 for venting carbon dioxide vapor from the container. Carbon dioxide is delivered to the container 10 by means of an injection pipe 20 which projects downwardly into the bath 12 through an opening 22 formed in the cover 16. To support the injection pipe 20, a plate 24 having an opening 26 is bolted to the cover 16 at a position with the openings 22 and 26 in alignment. An upstanding collar 28 is welded at 30 to the plate 24 and a set screw 32 is threadedly received in the wall of the collar 28 whereby the injection pipe 20 may be clamped in the desired, adjusted position. Y

At its upper or inlet end 34, the injection pipe 20 is connected to one branch of a conventional T-tting 36, A second branch is connected to the outlet of a shut-off valve 38, of conventional construction, which is connected by means of a conduit 40 to a schematically illustrated, refrigerated source 42 of liquid carbon dioxide under low temperature and its corresponding vapor pres sure, for example, 2 F. and 300 p.s.i.g., respectively.

The valve 38 functions to selectively prevent or permit the ow of liquid carbon dioxide from the source 42 through the conduit 40 into the injection pipe 20. The valve 38 is solenoid operated and is controlled by a switch 44 which in turn is regulated by a temperature sensitive element 46 which is suspended in the bath 12. Details of the valve 38, source of liquid carbon dioxide 42, the switch 44 and the temperature sensitive element 46 form no part of the present invention. Since each of these individual elements is commercially available, a detailed description of the structure of each is deemed unnecessary.

Details of the injection pipe 20, Whichmay be best appreciated by an examination of Fig. 2, includes a tabular jacket 48 and a tubular rFlow conduit 50`which' is mounted within the jacket 48 in spaced concentricfrelationship. Preferably, the conduit 50 is made of a mal terial, such as copper, having la relatively low specific heat, and with as thin a wall as permissible,`so as to have a minimum heat capacity allowing it to warm up quickly to the temperature of the liquid carbon dioxide without having a solidifying effect thereon. At the upper or inlet end of the injection pipe, the jacket 48 is sealed and secured to the fiow conduit 50 by means of a weldment 52. At the ,lower or dischargey end of the injection pipe, coupling fitting 5,4 is brazed or soldered to the lower end of the jack-et 4 8, as at 56, to define an external- 1y threaded extension 58'. The lower end of the fitting 54 snugly receives the lower end of the -ow conduit 50 and the fitting 54 is sealed thereto by braZing, or silver soldering, at 60. VThus, a sealed annular chamberis defined between the conduit 50 and the jacket which is filled with a suitable heat insulating material 62 which may take the form of asbestos rope Wrapped tightly around the ow conduit 50. This insulation helps in warming the Yconduit 5b to the temperature of the liquid carbon Vdioxide during the start-up period by preventing direct heat transfer from the conduit to the bath liquid. An orice plate 64 is mounted at the lower or discharge end of the ow conduit 50 and is provided with a restricted, centrally located orifice 66 through which 'carbon dioxide is discharged into the bath 12. In order to further reduce the possibility of soldifying the liquid carbon dioxide in the conduit 50 by heat transfer to the bath liquid, the orifice plate 64 is held in position at the lower end of the flow conduit 50 between two washers 68 of nonmetallic material having a relatively low heat conductivity characteristic. As shown in Fig. 2, the washers are disposed in face-to-face relationship with the plate The assembled washers 68 and plate 64 are clamped position at the end of the now conduit Sii by of a fitting 70 which is threadedly received upon the extension 58 of the coupling fitting 54. lBy virtue of the presence of the washers 68, the only direct metallic contact between the plate 64 and the bath, other thm the necessary exposure required for `the flow passage 72, is around the Yedge of thetoritice plate 64.

, In order to protect the outer surface of the jacket 48 lfrom vthe set screw 32, a shell or tubular shield 74 is welded on the outer surface of the jacket 48 to extend over the region at which the set screw 32 may engage the injection pipe 20.

In addition to connecting the injection pipe 20 to the valve 38, the T-fitting 36 also serves to place the. fio'w passage of the injection pipe in communication with an upwardly extending length of metallic tubing 76 which functions as 'a vapor trap in a manner to be described below. The unconnected upper end of the tube 76 is closed by mounting a pressure gauge 78 thereon. The tube 76 is constructed of relatively thin walled stock, since it is desirable that any carbon dioxide therein be maintained in the vapor phase by heat absorbed through thewall of the tube 76.

Y* In operation, the injection pipe 20 is inserted into the bath of liquid 12 to the desired depth which may be established by the set screw 32 to maintain the pipe in the desired position. Assuming that the valve 38 is opened to permit the ow of liquid carbon dioxide from the supply 42, the carbon dioxide Vwill iiow through the conduit 50 and be discharged into the bath through the orifice 66. By virtue -of the expansion of t-he liquid carbon dioxide as it passes through the orifice 66, it is transformed into a mixture of vapor and snow to cool the liquid in the bath 12. As liquid carbon dioxide ows through the valve 38 and into the injection pipe 20, the vapor in the upwardly extending tube 76 is trapped therein and subjected to the flow pressure. Also, since the external surface of the tube 76 is exposed directly to ambient temperature, the liquid carbon dioxide which ows'into the lower part of the tube 76 absorbs sufiicient heat to create additional vapor in the upper part of the tube.

When the bath 12 is cooled to the desired temperature, element d6 will 'function to actuate the switch 44 which in turn actuates the valve 38 to cut off communi- 4 cation between the source 42v and the injection pipe 20. In view of the distance between the discharge orifice 66 and the valve 38, a substantial amount of liquid carbon dioxide may remain within the flow conduit 50Vimmediately after the valve 38 is closed. However, this residual liquid carbon dioxide will be expelled through the orifice 66 by the pressure of the vapor that is trapped in the tube 76 before the pressure in the conduit drops below the triple point, and consequently before the liquid carbon dioxide is changed to a solid.

It is to be understood that't'ne form of this invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size, `and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the subjoined claims,

Having thus described the invention, I claim:

l. Means foi-,discharging liquid carbon dioxide comprising a conduit having an inlet end Aandan outlet end, delivery means connected to said inlet end for' supplying liquid carbon dioxide under its ow'n vapor pressure to said conduit, means defining a discharge orifice in the outlet end of said conduit, a shut-orf valve connected in said delivery means adjacent the inlet end of said conduit and operable to selectively prevent or permit iiow of liquid carbon dioxide from said delivery means into said conduit, and liquid carbon dioxide vaporizing trap in continuous open communication with said ,delivery means through a branch connection located adjacent the discharge side of said valve, said trap receiving liquid carbon dioxide from the delivery means, when th'e valve is operated to perr'nitrfiow into :said conduit, and discharging carbon dioxide vapor into said conduit, when the valve is operated to prevent ow into said conduit, to expel the residual liquid 'carbon dioxide from the conduit.

2. A carbon dioxide discharge device comprising a pipe having va discharge orifice located at one end thereof and an inlet located atthe other end thereof, conduit means connected to said inlet end for supplying liquid carbon dioxide under its own vapor pressure to said pipe, a shut-off valve connected in lsaid conduit means adjacent the inlet end of said conduit means and operable toselectively .prevent or permit ow of carbon dioxide from said conduit means into saidpipe, and means in continuous open communication with said conduit means between said shut-off valve and said inlet end of said `pipe for collecting and maintaining a charge of carbon dioxide vapor under pressure when said valve is operated to permit flow of liquid carbon dioxide from said conduit means into said pipe and for .releasing said charge of carbon dioxide vapor into said pipe to expel residual liquid carbon dioxide Vtherefrom when said valve is operated to prevent the yflow of liquid carbon dioxide from said conduit means into said pipe.

3. A device as defined in lclaim 2 wherein said means connected to said conduit-means comprises a hollow metal tube closed at one end and connected -at its other end to said conduit means to place the interior of said tube in communication with said conduit means and said pipe, said tube projecting upwardly from said conduit means and having its external surface exposed'dire'ctly to ambient temperature.

4. vA carbon dioxide discharge 4device Acomprising an elongated tubular jacket, a =ow conduit mounted Within said jacket in spaced concentric relationship thereto, means sealing said .jacket to said conduit' lat Veach end thereof to denne an 4annular chamber between said conduit and said jacket, heat insulating ymeans filling fsaid chamber, an orifice plate jlocated at one end 'of 's'aid flow conduit, a Vwasher of a material having relatively low heat conductivity characteristics lying Vagainst eac'h 'of theopposed faces of said-orificel plate, one of sa'id washers being vdisposed in face-to-facerelationship with said one end ofsaid ow conduit, means engageable with the ascenso other of said washers for clamping said washers and said orice plate to said one end of said ow conduit, delivery means connected to the other end of said conduit for supplying liquid carbon dioxide under pressure to said conduit, a shut-off valve connected in said delivery means adjacent said inlet end and operable to selectively prevent or permit ow of carbon dioxide from said deliveryl means into said pipe, and means connected to said delivery means between said shut-olf valve and said' inlet end of said pipe for collecting and maintaining a charge of carbon dioxide vapor under pressure when said valve is operated to permit ow of liquid carbon dioxide from said conduit means into said pipe and for releasing said charge of carbon dioxide vapor into said pipe to expel residual liquid carbon dioxide therefrom when said valve is operated to prevent the flow of liquid carbon dioxide from said conduit means into said pipe.

5. A device as defined in claim 4 wherein said means connected to said delivery means comprises a hollow metal tube closed at one end and connected at its other end to place the interior of said tube in communication with said delivery means and said pipe, said tube projecting upwardly from said delivery means and having its external surface exposed directly to ambient temperature.

6. A discharge device for liquid carbon dioxide comprising an elongated tubular jacket, a flow conduit mounted within said jacket in spaced concentric relationship thereto, means sealing said jacket to said conduit at each end thereof to define an annular chamber between said conduit and said jacket, heat insulating means filling said chamber, an orifice plate located at one end of said iiow conduit, a washer of a material having relatively low heat conductivity characteristics lying against each of the opposed faces of said orifice plate, one of said washers being disposed in face-to-face relationship with said one end of said iiow conduit, and means engageable with the other of said washers for clamping said washers and said orifice plate to said one end of said iiow conduit.

7. Means for cooling a bath of liquid by the injection of carbon dioxide at a low temperature into said bath, comprising an injection pipe having a discharge orifice located below the surface of said bath and an inlet end located at a point external of said bath, conduit means connected to said inlet end of said pipe for supplying liquid carbon dioxide under its own vapor pressure to the inlet end of said pipe, a shut-off valve connected in said conduit means adjacent said inlet end of said' pipe and operable to selectively prevent or permit oW of liquid carbon dioxide from said conduit means into said pipe, and a liquid carbon dioxide vaporizing trap in continuous open communication with said conduit means through a branch connection located adjacent the discharge side of said valve, said trap receiving liquid carbon dioxide from the conduit means, when the valve is operated to permit ow into said pipe, and discharging carbon dioxide vapor into said pipe, when the valve is operated to prevent ow into said pipe, to expel the residual liquid carbon dioxide from the pipe.

8. An injection pipe for use in a carbon dioxide cool ing system comprising an elongated tubular jacket, a ow conduit mounted within said jacket in spaced concentric relationship thereto, means sealing said jacket to said conduit at each end thereof to define an annular chamber between said conduit and said jacket, heat insulating means filling said chamber, an orice plate located at one end of said ow conduit, a Washer of a material having relatively low heat conductivity characteristics lying against each of the opposed faces of said orifice plate, one of said washers being disposed in face-to-face relationship with said one end of said flow conduit, and means engageable with the other of said washers for clamping said washers and said orifice plate to said one end of said flow conduit.

9. A discharge device for liquid carbon dioxide as dened in claim 6 further characterized by means connected to the other end of said ow conduit for supplying liquid carbon dioxide under its own vapor pressure to said conduit, a valve connected in said liquid carbon dioxide supply means adjacent said connected end of said flow conduit, said valve being operable to prevent or permit liow of carbon dioxide from said supply means to said ow conduit, and a liquid carbon dioxide Vaporizing trap in continuous open communication with said liquid carbon dioxide supply means through a branch connection located adjacent the discharge side of said valve, said trap receiving liquid carbon dioxide from said supply means, when the valve is operated to permit flow into said conduit, and discharging carbon dioxide vapor into said conduit, when the valve is operated to prevent flow into said conduit, to expel the residual liquid carbon dioxide from said conduit.

References Cited in the le of this patent UNITED STATES PATENTS 1,888,526 Catton Nov. 22, 1932 1,978,928 Blum Oct. 30, 1934 2,081,287 Aldridge May 25, 1937 2,181,853 McCloy Nov. 28, 1939 2,290,839 White July 2l, 1942 2,341,268 Davis Feb. 8, 1944 2,440,930 Camilli May 4, 1948 2,580,649 Bludeau Jan. 1, 1952 2,632,305 Matteson Mar. 26, 1953 2,772,921 Nance Dec. 4, 1956 

